/* ===== FONTS ===== */
@font-face {
  font-family: 'Inter';
  src: url('fonts/Inter-Regular.woff2') format('woff2');
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: 'Inter';
  src: url('fonts/Inter-Medium.woff2') format('woff2');
  font-weight: 500;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: 'Inter';
  src: url('fonts/Inter-SemiBold.woff2') format('woff2');
  font-weight: 600;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: 'Inter';
  src: url('fonts/Inter-Bold.woff2') format('woff2');
  font-weight: 700;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: 'JetBrains Mono';
  src: url('fonts/JetBrainsMono-Regular.woff2') format('woff2');
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

/* ===== VARIABLES ===== */
:root {
  --bg:          #0d1117;
  --bg-sidebar:  #161b22;
  --bg-card:     #1c2128;
  --bg-card-2:   #22272e;
  --border:      #30363d;
  --text:        #e6edf3;
  --text-muted:  #8b949e;
  --text-dimmed: #6e7681;

  /* Unidades */
  --unit-1: #00d4ff; /* Campo eléctrico      Aux 1–3   */
  --unit-2: #3fb950; /* Potencial/conductores Aux 4–9  */
  --unit-3: #d29922; /* Pre-control/dipolos   Aux 10–11*/
  --unit-4: #f0883e; /* Dieléctricos          Aux 12–14*/
  --unit-5: #bc8cff; /* Corrientes/circuitos  Aux 15–16*/
  --unit-6: #f472b6; /* Magnetismo            Aux 17–18*/
  --unit-7: #ef4444; /* Gases reales/transp.  Termo Cát. 24–28 */

  --sidebar-w: 260px;
  --content-max: 820px;
  --radius: 8px;
  --radius-sm: 4px;
}

/* ===== RESET ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  font-size: 15px;
  display: flex;
  min-height: 100vh;
}

/* ===== SIDEBAR ===== */
.sidebar {
  width: var(--sidebar-w);
  height: 100vh;
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border);
  position: fixed;
  top: 0;
  left: 0;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  z-index: 100;
}

.sidebar-header {
  padding: 20px 20px 16px;
  border-bottom: 1px solid var(--border);
}

.sidebar-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text);
}

.sidebar-logo .icon {
  font-size: 22px;
  line-height: 1;
}

.sidebar-logo .name {
  font-weight: 700;
  font-size: 15px;
  letter-spacing: -0.02em;
}

.sidebar-logo .subtitle {
  font-size: 11px;
  color: var(--text-muted);
  font-weight: 400;
}

.sidebar-nav {
  padding: 12px 8px;
  flex: 1;
}

.nav-section-title {
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-dimmed);
  padding: 8px 12px 4px;
  margin-top: 8px;
}

.nav-section-title:first-child { margin-top: 0; }

.nav-link {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  text-decoration: none;
  color: var(--text-muted);
  font-size: 13.5px;
  transition: background 0.15s, color 0.15s;
  position: relative;
}

.nav-link:hover {
  background: var(--bg-card);
  color: var(--text);
}

.nav-link.active {
  background: var(--bg-card-2);
  color: var(--text);
  font-weight: 500;
}

.nav-link .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  flex-shrink: 0;
}

.nav-link .num {
  font-size: 11px;
  color: var(--text-dimmed);
  font-family: 'JetBrains Mono', monospace;
  min-width: 20px;
}

/* ===== MAIN CONTENT ===== */
.main {
  margin-left: var(--sidebar-w);
  flex: 1;
  padding: 40px 48px;
  max-width: calc(var(--sidebar-w) + var(--content-max) + 96px);
}

.content {
  max-width: var(--content-max);
}

/* ===== HERO ===== */
.hero {
  margin-bottom: 40px;
}

.hero-tag {
  display: inline-block;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-dimmed);
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 3px 10px;
  margin-bottom: 14px;
}

.hero h1 {
  font-size: 32px;
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.2;
  margin-bottom: 10px;
}

.hero p {
  color: var(--text-muted);
  font-size: 15px;
  max-width: 560px;
  line-height: 1.7;
}

/* ===== PAGE HEADER (aux pages) ===== */
.page-header {
  margin-bottom: 36px;
  padding-bottom: 28px;
  border-bottom: 1px solid var(--border);
}

.page-header .breadcrumb {
  font-size: 12px;
  color: var(--text-dimmed);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.page-header .breadcrumb a {
  color: var(--text-muted);
  text-decoration: none;
}
.page-header .breadcrumb a:hover { color: var(--text); }

.page-header .unit-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  border-radius: 20px;
  padding: 3px 10px;
  margin-bottom: 12px;
  border: 1px solid;
  opacity: 0.9;
}

.page-header h1 {
  font-size: 28px;
  font-weight: 700;
  letter-spacing: -0.025em;
  line-height: 1.2;
  margin-bottom: 8px;
}

.page-header .desc {
  color: var(--text-muted);
  font-size: 14px;
}

/* ===== SECTION ===== */
section {
  margin-bottom: 36px;
}

section h2 {
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

section h2 .section-icon {
  font-size: 15px;
  opacity: 0.8;
}

section h3 {
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text);
}

/* ===== CARDS ===== */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 20px;
  margin-bottom: 12px;
}

.card-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

@media (max-width: 600px) {
  .card-grid { grid-template-columns: 1fr; }
}

.concept-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 18px;
}

.concept-card h3 {
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 6px;
}

.concept-card p {
  font-size: 13.5px;
  color: var(--text-muted);
  line-height: 1.65;
}

/* ===== FORMULA BLOCK ===== */
.formula-block {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-left: 3px solid;
  border-radius: var(--radius);
  padding: 16px 20px;
  margin-bottom: 12px;
}

.formula-block .formula-label {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-dimmed);
  margin-bottom: 10px;
}

.formula-block .formula-math {
  font-size: 16px;
  margin-bottom: 10px;
  overflow-x: auto;
}

.formula-block .formula-desc {
  font-size: 12.5px;
  color: var(--text-muted);
  line-height: 1.6;
  border-top: 1px solid var(--border);
  padding-top: 10px;
  margin-top: 4px;
}

.formula-block .formula-desc code {
  font-family: 'JetBrains Mono', monospace;
  font-size: 11.5px;
  background: var(--bg-card-2);
  padding: 1px 5px;
  border-radius: 3px;
  color: var(--text);
}

/* ===== TOPIC LIST ===== */
.topic-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.topic-list li {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.5;
}

.topic-list li::before {
  content: '→';
  flex-shrink: 0;
  font-size: 12px;
  margin-top: 2px;
  opacity: 0.5;
}

/* ===== TIP BOX ===== */
.tip-box {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 20px;
}

.tip-box .tip-title {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text-dimmed);
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.tip-box ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.tip-box ul li {
  font-size: 13.5px;
  color: var(--text-muted);
  padding-left: 16px;
  position: relative;
  line-height: 1.55;
}

.tip-box ul li::before {
  content: '•';
  position: absolute;
  left: 4px;
  color: var(--text-dimmed);
}

/* ===== INDEX TABLE ===== */
.temario-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13.5px;
}

.temario-table thead tr {
  border-bottom: 1px solid var(--border);
}

.temario-table th {
  text-align: left;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--text-dimmed);
  padding: 8px 12px;
}

.temario-table td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}

.temario-table tr:last-child td { border-bottom: none; }

.temario-table tr:hover td { background: var(--bg-card-2); }

.temario-table .aux-num {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  color: var(--text-dimmed);
  white-space: nowrap;
}

.temario-table .aux-name a {
  color: var(--text);
  text-decoration: none;
  font-weight: 500;
}

.temario-table .aux-name a:hover { text-decoration: underline; }

.temario-table .aux-topics {
  color: var(--text-muted);
  font-size: 12.5px;
  line-height: 1.5;
}

/* ===== UNIT GROUP ===== */
.unit-group {
  margin-bottom: 40px;
}

.unit-group-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border);
}

.unit-group-header .unit-line {
  width: 28px;
  height: 3px;
  border-radius: 2px;
  flex-shrink: 0;
}

.unit-group-header h2 {
  font-size: 16px;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin: 0;
}

.unit-group-header .unit-range {
  margin-left: auto;
  font-size: 11px;
  color: var(--text-dimmed);
  font-family: 'JetBrains Mono', monospace;
}

/* ===== UNIT COLOR HELPERS ===== */
.u1 { color: var(--unit-1); border-color: var(--unit-1); }
.u2 { color: var(--unit-2); border-color: var(--unit-2); }
.u3 { color: var(--unit-3); border-color: var(--unit-3); }
.u4 { color: var(--unit-4); border-color: var(--unit-4); }
.u5 { color: var(--unit-5); border-color: var(--unit-5); }
.u6 { color: var(--unit-6); border-color: var(--unit-6); }
.u7 { color: var(--unit-7); border-color: var(--unit-7); }

.bg-u1 { background: color-mix(in srgb, var(--unit-1) 12%, transparent); }
.bg-u2 { background: color-mix(in srgb, var(--unit-2) 12%, transparent); }
.bg-u3 { background: color-mix(in srgb, var(--unit-3) 12%, transparent); }
.bg-u4 { background: color-mix(in srgb, var(--unit-4) 12%, transparent); }
.bg-u5 { background: color-mix(in srgb, var(--unit-5) 12%, transparent); }
.bg-u6 { background: color-mix(in srgb, var(--unit-6) 12%, transparent); }
.bg-u7 { background: color-mix(in srgb, var(--unit-7) 12%, transparent); }

/* ===== NAV COLORS ===== */
.dot-u1 { background: var(--unit-1); }
.dot-u2 { background: var(--unit-2); }
.dot-u3 { background: var(--unit-3); }
.dot-u4 { background: var(--unit-4); }
.dot-u5 { background: var(--unit-5); }
.dot-u6 { background: var(--unit-6); }
.dot-u7 { background: var(--unit-7); }

/* ===== PREV/NEXT ===== */
.page-nav {
  display: flex;
  gap: 12px;
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
}

.page-nav a {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 14px 16px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  text-decoration: none;
  color: var(--text);
  transition: border-color 0.15s;
}

.page-nav a:hover { border-color: var(--text-muted); }

.page-nav a.next { align-items: flex-end; }

.page-nav .nav-dir {
  font-size: 11px;
  color: var(--text-dimmed);
  margin-bottom: 4px;
}

.page-nav .nav-title {
  font-size: 13px;
  font-weight: 500;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 768px) {
  .sidebar {
    transform: translateX(-100%);
    transition: transform 0.2s;
  }
  .sidebar.open { transform: translateX(0); }
  .main { margin-left: 0; padding: 24px 20px; }
  .card-grid { grid-template-columns: 1fr; }
  .temario-table .aux-topics { display: none; }
}

/* ===== TYPST FORMULAS ===== */
.typst-formula {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 0 auto;
}

/* ===== SCROLLBAR ===== */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-dimmed); }

/* ===== QUIZ ===== */
.quiz { display: flex; flex-direction: column; gap: 20px; }

.quiz-q {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 24px;
}

.quiz-question {
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 14px;
  line-height: 1.6;
}

.quiz-options { display: flex; flex-direction: column; gap: 8px; margin-bottom: 14px; }

.quiz-option {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 10px 14px;
  border-radius: 8px;
  border: 1px solid var(--border);
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
  user-select: none;
}

.quiz-option input[type="radio"] { display: none; }

.quiz-option:hover { border-color: var(--text-muted); background: var(--bg-card-2); }

.quiz-option.selected { border-color: var(--text-muted); background: var(--bg-card-2); }
.quiz-option.selected .opt-letter { color: var(--text); border-color: var(--text-muted); }
.quiz-option.selected .opt-text { color: var(--text); }

.quiz-option.correct {
  border-color: #3fb950;
  background: rgba(63, 185, 80, 0.10);
}
.quiz-option.correct .opt-letter {
  color: #3fb950;
  border-color: #3fb950;
  background: rgba(63, 185, 80, 0.15);
}
.quiz-option.correct .opt-text { color: var(--text); }

.quiz-option.incorrect {
  border-color: #f85149;
  background: rgba(248, 81, 73, 0.10);
}
.quiz-option.incorrect .opt-letter {
  color: #f85149;
  border-color: #f85149;
  background: rgba(248, 81, 73, 0.15);
}
.quiz-option.incorrect .opt-text { color: var(--text); }

.opt-letter {
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  font-weight: 700;
  color: var(--text-dimmed);
  background: var(--bg-card-2);
  border: 1px solid var(--border);
  border-radius: 4px;
  width: 20px;
  height: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  margin-top: 1px;
  transition: color 0.15s, border-color 0.15s, background 0.15s;
}

.opt-text { font-size: 13.5px; color: var(--text-muted); line-height: 1.5; }

.quiz-btn {
  background: var(--bg-card-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  font-size: 13px;
  font-weight: 500;
  padding: 8px 16px;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
  font-family: inherit;
}

.quiz-btn:hover:not(:disabled) { border-color: var(--text-muted); background: #2d333b; }
.quiz-btn:disabled { opacity: 0.45; cursor: default; }

.quiz-feedback {
  display: none;
  margin-top: 14px;
  padding: 12px 14px;
  border-radius: 8px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--text-muted);
  border: 1px solid var(--border);
  background: var(--bg-card-2);
}

.fb-correct { color: #3fb950; font-weight: 600; }
.fb-incorrect { color: #f85149; font-weight: 600; }